Apparatus for pressing detergent bars and cakes



7 March 22, 1966 w, w, SWEET ETAL 3,241,208

APPARATUS FOR PRESSING DETERGENT BARS AND CAKES 2 Sheets-Sheet 1 FiledDec. 22. 1960 IN V EN TORS WAREfN W/LL/AMSWEET C HARL ES FEEDER/CAFISCHER ATTORNEY March 22, 1966 APPARATUS FOR PRESSING DETERGENT BARSAND CAKES Filed Dec. 22, 1960 w. w. SWEET ET AL 2 Sheets-Sheet 2INVENTORS WARREN WILL/AM SWEET YCHARLESFRFDER/CKF/SCHB? WZM AITORNFYUnited States Patent 3,241,208 APPARATUS FOR PRESSING DETERGENT BARS ANDCAKES Warren William Sweet, Pompton Plains, and Charles FrederickFischer, Jersey City, N.J., assignors to Colgate-Palmolive Company, NewYork, N.Y., a corporation of Delaware Filed Dec. 22, 1960, Ser. No.77,682 4 Claims. (Cl. 25-7) This application is a continuation-impart ofapplication Serial No. 765,712, filed October 2, 1958, which in turn isa continuation-in-part of application Serial No. 288,022, filed May 15,1952.

The present invention relates to an apparatus and proc ess for pressingdetergent materials into the forms of bars and cakes and has particularreference to die members and die boxes, formed partially or wholly ofplastic materials.

One form of apparatus which has been used for pressing detergentmaterials into the forms of bars and cakes comprises a die set,including a pair of companion die members and a die box, mounted inoperative relationship on a stamping or pressing machine.

The die sets of such apparatus have been wholly formed of various kindsof metals and alloys, e.g., steel, iron, copper, aluminum, bronze, Monelmetal, etc. Dies and die boxes made of these metals, although widelyused in the detergent industry, have certain inherent limitations,disadvantages and drawbacks which limit their usefulness anddesirability for commercial detergent pressing operations.

The construction of metal die members, for example, necessitatespainstaking and time consuming hand shaping and machining operations.When a metal die member wears out or is broken it is difficult toreplace it with an exact duplicate replacement die since the replacementdie must also be shaped individually by hand, molded metal dies nothaving been found practicable. Another disadvantage inherent in die setsmade of shaped or machined metals is the fact that, because the shape ofthe die member does not conform exactly with the die box walls, acertain amount of detergent material escapes from be tween the workingfaces of the die members during pressing and flows into the clearancespace between the dies and the interior walls of the die box, producinga socalled fin or flash. In time some of the detergent flash builds upon the faces of the dies and mars the surfaces of subsequently pressedcakes. The cleaning of the dies and the die box to remove this fin orflash necessitates shutting down the apparatus, which results inincreased labor and production costs and, if cakes of soap or detergenthad been produced by the dies upon which flashing was deposited, thatproduction would have to be scrapped. Had the manufacture of this marredproduct not been noticed, and the soap been shipped, bars put on salewould be unsightly to the consumer and would probably create anunfavorable impression about the quality of the detergent itself. Thismight very well lead to a loss of customers for the product, as well asdamage to the manufacturers valuable reputation for selling onlyproducts of the highest quality.

Difliculties similar to those described in the preceding paragraph arealso encountered when the detergent or soap being pressed is attractedto the material of the die and a portion adheres to the die duringpressing. This behavior is not usually as frequent or as detrimental asthe deposition of flashing on the die. It occurs most often when the diehas a rough or figured working surface and when the material beingpressed is soft and lacks cohesion. It has been observed that metal hasan affinity for detergents (including soaps), sometimes causing severediemarking when detergent adheres to it.

3,241,208 Patented Mar. 22, 1966 It has been discovered that thedisadvantages and limitations heretofore encountered in pressingdetergent materials with metal die sets may be overcome or substantiallyminimized by pressing the detergent in a die set formed of organicplastic materials. This improvement is especially notable when the diesare used to press softer, tackier detergents, which tend to adhere tometal dies. The novel plastic die members of this invention are ruggedand long wearing and may be mounted quickly for operation inconventional pressing machines. They are rigid, comparable to stainlesssteel, Monel metal or brass, in this respect, closely molded to fit thedie boxes so that no objectionable flashing of detergent occurs duringthe pressing operation. This absence of flashing is apparently due tothe resistance of the detergent to flowing through the very smallopenings present at the pressure employed and during the short time,usually a split second, in which the detergent is shaped.

In US. Patent No. 2,965,946, of which this application is acontinuation-in-part, various plastics were suggested for soap anddetergent pressing die materials. Particularly desirable were thoseplastics which were flexible enough to expand to the inner walls of thedie box during pressing, thereby preventing flashing of detergent. Suchmaterials are very useful in allowing the easy, economical pressing ofsoap and detergent bars at high speeds without die markings andexcessive flashings. Yet, in presses which malfunction to cause theplacement of more than one blank of detergent in the die box, the moreflexible and resilient dies may be prematurely expanded, causingbreakage or a permanent distortion when forced against the front of thedie box during pressing. When metal dies are employed, double blanks'merely result in overweight double cakes, the dies being suflicientlyrigid to prevent expansion of the edges and resultant contact with thedie box, despite the spreading force due to the presence of the extrablank of detergent. Now it has been found that certain plastic dies canbe made with qualities like those of metal dies, so that the dies may bemade of substantially the size of the die box, with only a minimalclearance allowed, and will not expand during pressing of the detergent.Such dies are known as epoxies or epoxy resins. They are hard and pressdetergent cakes of excellent surface smoothness. They are tough and canbe employed continuously in pressing soaps for six months and morewithout replacement or dressing being needed. They are non-adherent tosoaps and anionic synthetic detergents despite their accepted use astenacious adhesives; thus, there is no serious problem of die mark ingdue to sticking of detergent on the die faces. Agents to promote releaseof the pressed detergent need not be used in as great amount as isnecessary with metal dies. The epoxies are inert and do not interactwith pressing solution, thus do not form compounds which detrimentallyaffect the pressed detergent. Furthermore, they have unusually desirablemolding characteristics which allow the production of dies in the trueshape of the molds employed, without objectionable shrinkage ordistortion. They are thermosetting, therefore little affected in theirphysical properties by normal changes in temperature. By the use ofdifferent types and different proportions of reactants and hardeners orcuring agents, a fairly broad range of properties is obtainable in thefinished dies. Such alterations of properties can also result fromutilization of different fillers and plasticizers and variations of theamounts thereof.

Epoxy resins may be made from a variety of epoxycontaining materials,aromatic or aliphatic hydroxyl containing compounds and curing agents.Several dilferent types are commercially available, some of which willbe described below.

The most important currently used epoxy resins are those derived fromepichlorhydrin and bisphenol A. These are reacted in the presence ofcaustic to produce the diglycidyl ether of bisphenol A, it usually beingdesirable to use an excess of epichlorhydrin to obtain high yields ofmonomer. The monomer can be polymerized by caustic or adehydrohalogenating compound to form resins of greater chain length andhigher viscosities. Higher molecular weight resins are of highersoftening points and also of higher epoxide equivalents. Other methodsof producing these resins may also be employed and other reactants willalso result in useful epoxies. Thus, monoglycidyl ethers may be made, inwhich there is a second reactive point such as an olefinic bond, e.g.,allyl glycidyl mixed diether of bisphenol A. Instead of epichlorhydrin,dichlorhydrin, 1,2-dichloro-3 hydroxy propane, butadiene dioxide ordiglycidyl ether may be used to supply the epoxy radical. Instead ofbisphenol A, other polynuclear polyhydroxy phenols may be substituted,e.g., bisphenol F, 4,4 dihydroxy diphenyl, trihydroxyl diphenyl dimethylmethane, dihydroxyl diphenyl sulfone, Novolac resins and long chainbisphenols. Polyalcohols, such as ethylene glycol, glycerol, erythritoland 2,3-butanediol are useful, as are mononuclear diand trihydroxyphenols such as resorcinol, hydroquinone, pyrocatechol, saligenin andphloroglucinol. The most important of the resins, other than diglycidylether of bisphenol A are the glycidyl ethers of glycerol, glycidylethers of bisphenol F, epoxylated Novolacs and glycidyl ethers oflong-chain bisphenol. Mixtures of such resins may be made and theepoxies may be compounded with other plastics to obtain special effects.

Epoxy resins are produced by many manufacturers and are usually sold bytrade name, together with physical specifications. Among the betterknown epoxies are Araldite (Ciba); Bakelite (Union Carbide); Cardolite(Irvington Chemical Division of Minnesota Mining and Mfg. Co.); Epiphen(Borden); Epi-Rez (Devoe-Raynolds); Epon (Shell); Epotuf (Reichhold);Tygofil, Tygoweld (U.S. Stoneware); and Epoxylite (Epoxylite Corp.);others include Airtemp, Codco, Cellobond, Cepox, Cordopreg, Corrocote,Devcon, Ecco, Epocast, Epolac, Epolite, Helix, Hysol, Marblette, Nureco,Polykast, Polytool, Ren, Rezolin, Stycast, Tylene, Fiberite, Eccomold,and Tybon 5621-6, also FMCs Oxiron and Bordens Epoxide-201.

Resin viscosities usually are within the range from 150 to 100,000centipoises or higher, as measured at C. Solid resins are dissolved inbutyl carbitol (40% solution). Epoxide equivalents are generally fromabout 140 to as high as 4,000. The average molecular weight of the mostuseful commercial resins is from 300 to 4,000. Their softening pointsusually lie between 8 C. or lower and 150 C.

The epoxy resins are further polymerized and cross linked during curinginto thermoset compounds by means of hardening agents. Such hardeningagents catalyze polymerization and sometimes form linking parts of thepolymer. Epoxy-epoxy polymerization is promoted by tertiary amines aswell as available ions and active hydrogens. Hydroxyl polymerization iscatalyzed by acids, bases and amines, primary, secondary and tertiary.Crosslinking agents include polyfunctional primary and secondary amines,organic acids and anhydrides.

Among the useful tertiary amines are triethylamine, benzyldimethylamine,alpha-methylbenzyl dimethylamine, DMP-IO and DMP-30. Tertiary aminesalts, such as the triacetates, tribenzoates and the tri-Z-ethyl hexoateof DMP- increase resin pot lives. The primary aliphatic amines includediethylene triamine and diethylamino propylamine. Modified amines,including amides, metaphenylene diamine, amine glycidyl adducts andboron trifluoride complexes are also used. Among the useful cyclicamines piperidine and its derivatives are representative. The organicacid curing agents are usually carboxylic acids. A preferred anhydrideis phthalic anhydride.

The proportion of curing agent employed generally determines thephysical properties of the thermosetting epoxy. As a rule the reactantsshould be about in that proportion which results in one epoxy per activehydrogen of the curing agent. Variations from this proportion should notbe greater than 20%. With catalyzed reactions the proportion of catalystshould be regulated to secure the desired properties. Sometimes suchproperties may also be controlled by incorporation of fillers, such assilica, asbestos, glass or wood flour.

The typical finished epoxy, cast or molded into a soap pressing die, hasan impact strength of about 0.2 to 1 ft. lb. per inch of notch byAmerican Society for Testing Materials test D-256. Its compressivestrength is from 1.3 to 2.8 x 10 lbs/sq. in. (ASTM, D-695). Rockwellhardness is M- to M- (ASTM, D-785). It has a modulus of elasticity intension of 13.5 x 10 lbs/sq. in. (ASTM, D-638) for an unfilled moldedepoxy, a flexural strength (ASTM, D-290) of 8,000 to 21,000 lbs/sq. in.and a specific gravity (ASTM, D-792) of 1.1 to 2.0. Such an epoxy canindefinitely resist maximum temperatures of 250 F. to 600 F. and has aheat distortion temperature (ASTM, D648) of 100 F.to 550 F.

Examples of epoxy resins suitable for detergent pressing dies includethat made from 100 parts Epon 828 epoxy resin of average molecularweight of 350 to 400 and 10 parts diethylene triamine curing agent, castand cured for 8 hours at room temperature. Another good hard die can bemade from 100 parts of epoxy resin of epoxide equivalent of 0.20 and17.8 parts pyromellitic dianhydride, cured for 10 minutes at C. Alsosuitable is a die set made from 92 parts of Union Carbides Epoxide 201epoxy resin (3,4-epoxy-6-methyl cyclohexylmethyl- 3,4-epoxy 6methylcyclohexane carboxylate), cured 6 hours at 320 F. Die materialssuccessfully tested include that made from 100 parts epoxy resin SW 404(made by CIBA of Switzerland) and 9 parts S 404 hardener cured for 8hours at room temperature. Less satisfactory, but acceptable, is thatresulting from reacting 100 parts of Bakelite (England) Rl9019 resinwith 19 to 24 parts Q 18814 hardener and curing at room temperature. Thedie resulting is clear amber and has a flexural strength of 17,000lbs/sq. in., modulus of elasticity of 3.6 x 10 lbs/sq. in., compressivestrength of 13,500 lbs./sq. in. and a heat distortion point of 50 C.

The above described materials have been found to be unexpectedly usefulas detergent pressing dies. They successfully withstand the repeatedshocks of pressing, readily release the pressed soap and can be easilyproduced by molding or casting to such accuracy that they will closelyfit the die box and prevent objectionable flashing, even though the dieis of the order of inflexibility of steel. If desired the die box itselfor a liner fitted to it may be made of epoxy resin or other suitablenongall-ing plastic, e.g., polyethylene, Micarta, polypropylene, nylonor other suitable high organic polymer.

In order to indicate more fully the operations of the novel detergentpressing appartus, reference is made to the following description takenin conjunction with the accompanying drawings which, by way ofillustration, show a preferred embodiment of the invention. Otherembodiments of the invention employing the same or equivalent principlesmay be used and structural changes may be made as desired withoutdeparting from the present invention and going outside the purview ofthe appended claims. In the drawings similar reference characters areused to designate corresponding parts in each of the several figures.

In the drawing:

FIG. 1 is a perspective view, with parts broken away for greaterclarity, of apparatus embodying features of the invention;

FIG. 2 is a front view of a plastic die member;

FIG. 3 is a sectional view of the die member shown in FIG. 2, along line33, looking in the direction of the arrows;

FIG. 4 is a sectional View of a novel plastic die set, including a pairof plastic die members and a die box, showing the relative position ofthe parts before the die members are brought towards one another duringthe pressing stroke;

FIG. 5 is a sectional view similar to FIG. 4 showing the relativeposition of the parts and a pressed detergent cake upon completion ofthe pressing stroke;

FIG. 6 is a fragmentary view of a die box spider showing a die box, areceiving cavity and a plastic liner and FIG. 7 is an enlargedfragmentary sectional view of the die box and liner shown in FIG. 6,along line 7'7, looking in the direction of the arrows.

Referring to the drawings, the invention. as therein illustrated, isembodied in apparatus including die members of epoxy resin plasticmaterials designed for pressing detergent bars of rounded rectangularshape. Other bar shapes may be pressed by die sets of correspondingdesign.

Looking first at FIG. 1, apparatus for pressing detergent material intothe forms of bars and cakes is depicted. The reference character 10designates a die box spider which is cruciform in shape and which isadapted to rotate counter clockwise (as shown on the drawing) about anaxis perpendicular to lines through the middle of each pair of oppositearms of the spider and at the point of intersection. There is a die boxll, having a rectangular receiving cavity 12 located in each arm, thedirection of the cavity being parallel to the axis of rotation of thespider. Means (not shown in the figure) are provided for rotating thespider through 360 in 90 increments.

A guide box 14, having lateral walls 15 spaced apart by a distanceapproximately equal to the length of a receiving cavity, is locatedadjacent the spider. The upper part of the guide box is closed off by apair of stops 16. A shoulder 18 is located at a distance below saidstops approximately equal to the width of a receiving cavity. The stops,shoulder and lateral walls of the guide box together form a port ofapproximately the same cross section as a receiving cavity. The port isextended a short distance from the guide box in the direction of thespider. The guide box is so located that said port is in horizontalalignment with each receiving cavity successively as the cavities arerotated into the lowermost position of the spider after each 90 rotationof said spider. A horizontally reciprocating bottom pusher 20 ispositioned in alignment with said port and is adapted for reciprocablemotion in and out of the guide box.

A vertical pusher 22, adapted to reciprocate vertically in the guidebox, is provided. A conveyor fade belt 21 mounted upon rollers 24, oneof which (not shown) is driven by positive means, has its forward endpositioned in the guide box 14. Pusher 22 is adapted to reciprocate froma position below the forward end of the conveyor belt, to a position inalignment with the shoulder.

Adjacent the spider and at a position 90 forward from the lowermostpoint thereof there is a pair of cured epoxy resin companion plastic diemembers 26 of approximately the same cross section adapted forhorizontal reciprocation into each of the cavities l2 successively uponregistry of the spider.

A horizontal reciprocating top pusher 28 is located adjacent the spiderin horizontal alignment with a receiving cavity at the uppermostposition of the spider. Pusher 28 is adapted to reciprocate through eachof said cavities successively upon registry of the spider. A take-offbelt 30 is located below the uppermost cavity on the side of the spideropposite the top pusher and conveys pressed detergent cakes 31 (oneshown) to a wrapping station or the like.

Looking next at FIGS. 2 and 3, an epoxy resin plastic die member 26 isshown in the form of a block having a body portion provided with adepressed working surface or face 32. The peripheral portion of thedepressed face curves outwardly and joins side walls 34 of the block toterminate in a hard thin edge 36. If desired, trademarks, trade namesand the like may be embossed on or engraved in working face 32 formarking the pressed bar.

The die member 26 is secured to a mounting plate 38 in any convenientmanner as by machine screws 40. The plate 33 is secured to a shaft 42attached to a detergent press. Sometimes it may be desirable to mold orcast the plastic material about an insert which is readily fastenable tothe detergent press to hold the die in correct position.

Looking next at FIGS. 4 and 5, there is shown a plastic die setcomprising a die box 11 and a pair of relatively movable hard epoxyresin die members 26. As illustrated in the drawing the die box is madeonly very slightly larger in size than the die member to provide aclearance space 46 (usually from 0.0005 to 0.002 inch) which allows forpassage of the die members in and out of the box, while still preventingflashing. The size to the clearance space has been exaggerated in thedrawing for purposes of clarity of description.

In FIG. 4 the die members are shown in the position in which they appearnear the beginning of the pressing stroke. FIGURE 5 shows the positionof the die members at the end of the pressing stroke.

Looking next at FIGS. 6 and 7, a die box 11 having a liner 48 of thesame epoxy resin as the dies or of other suitable non-galling plastic,is shown in a receiving cavity 12. Die box 11 comprises two portions 50and 52 joined to one another at 54 and held by any convenient means,e.g., by machine screws 56. As shown more clearly in FIG. 7, thatsurface of die box 11 which defines cavity 12 is provided with a grooveor notch 58, i.e., the notch extends about the perimeter of cavity 12 inbox 11. The outer surface of plastic liner 48 is provided with anintegrally formed perimetrically extending ridge 60. To assemble theparts it is only necessary to remove portion 52 from portion 50 of thedie box, insert liner 48, replace die box portion 52, and insert andtighten screws 56. Ridge 60 of liner 48 fits securely within notch 58and maintains the liner in fixed position.

Each of the companion die members 26 is preferably substantially whollyformed of hard thermoset epoxy resin plastic although only the workingsurfaces thereof, those contacting the detergent to be pressed, are mostdesirably of such material. Within the broader area of this inventionare contemplated detergent pressing apparatuses in which the die membersare of metal alloy or other hard base material covered with a layer orcoating of plastic of suitable thickness.

The operation of the detergent pressing apparatus of this invention issimple and now will be described with respect to the die pressing of amilled detergent blank, such as either soap alone or a combinationsoap-synthetic detergent bar comprising mixed sodium soaps of higherfatty acids and monoglyceride sulfate anionic synthetic organicdetergent. The apparatus employed in the pressing operation to bedescribed includes a liner for the die box cavity and a pair ofcompanion plastic die members, each made of hard epoxy resin thermosetplastic, such as CIBAs SW 404. It will be understood that thedescription also applies to apparatuses and processes using othersuitable plastics, as taught by this specification.

Blanks of the milled detergent having a length of about 3 /2 and a widthof 2" are fed into the guide box 14 by the moving conveyor belt 21.Vertical pusher 22 raises one of said blanks to the top of the guide boxwhere the same is held by the lateral pressure of the walls 15 of theguide box. Bottom pusher 20 pushes the blank into the port of the guidebox where 7 it is held by the shoulder 18. In the next upward stroke ofvertical pusher 22 a second blank is raised to the top of the guide boxand the next forward stroke of the bottom pusher pushes said secondblank into the port, thereby pushing the first blank from the guide boxinto a receiving cavity 12 at the lowermost position of the spider. Thespider then is rotated 90 and the detergent is in position for beingpressed between dies 26.

The dies 26 are brought forcibly towards one another with suflicientpressure, usually from to 1000 pounds per square inch, e.g., about 250pounds per square inch to form and press the blank into a cake ofdetergent having the shape of the cavity defined by the dies and the diebox. While the blank is being pressed into shape, at the edges 36 of thedies 26 detergent is forced in the direction of the clearance space,but, because the clearance is small, the detergent is viscous and thepressing period is less than a second, none of the detergent flows intoand through clearance space 46.

The dies then are withdrawn and the spider again is rotated carrying thepressed cake into the uppermost position. Top pusher 28 then ejects saidcake from the cavity whence it falls onto the take-off conveyor 30.

A lubricating material, e.g., mineral oil, carbitol, acetic acid,glycerine, salt solutions, pulverized solids, etc., may be used, ifdesired, in pressing detergent materials with the apparatus of thisinvention. If a lubricant is used it may be applied most advantageouslyto the blanks while the same are being carried to the guide box byconveyor belt 21. Only a minor amount of lubricant need be used, i.e.,only about one or two drops need be applied to every fifth or sixthdetergent blank.

The detergent pressing apparatus, including die sets of suitableplastics described herein, is adapted for pressing bars and cakes ofsoaps or synthetic detergents of various compositions employed in theart. It is a particular feature of the invention that blanks and barscomprising synthetic detergents, with or without fatty acid soaps inadmixture therewith, can often be pressed without sticking to the dieand die box, although these materials are frequently, strongly adherentto metal parts.

The plastic die sets of the present invention may be produced readilyand easily by well-known commercial manufacturing processes. The diemembers may be made by molding or casting. Thus, it is a relativelysimple matter, when a plastic die member becomes unusable, to replacethe same with another member which is an exact duplicate of the first.Furthermore, a great saving in labor costs is realized since theconstruction of an accurate plastic die duplicate, unlike themanufacture of metal dies, does not necessitate painstaking and timeconsuming hand shaping operations.

While there has been described what is at present considered to be thepreferred embodiment of the invention, it will be understood, of course,that many modifications and changes and substitutions may be madetherein without departing from the true scope of the invention asdefined in the appended claims.

All percentages and proportions given in the specification and in theclaims are by weight, unless otherwise specified.

What is claimed is:

1. Apparatus for pressing detergent materials into cake form comprisinga pair of relatively movable companion die members and a die box, saidmovable die members each having a working surface of hard, rigidthermoset epoxy resin polymer and being substantially composed of saidpolymer, the movable die members being of shape which conforms with thedie box walls and clears them, the clearance space being small enough toprevent flashing of detergent past the dies during pressing, said epoxyresin polymer having impact strength of about 0.2 to 1 ft. lb. per inchof notch, a Rockwell hardness of about M 80 to M 120, a compressivestrength of about 1.3 to 2.8 x 10 lbs/sq. in., a ftexural strength ofabout 8,000 to 20,000 lbs./ sq. in. and a heat distortion temperature ofF. to 550 F.

2. Apparatus according to claim 1 in which the epoxy resin polymer isthat resulting from reaction of an epoxy resin of molecular weight of300 to 4,000 with 80 to 120% of the stoichiometric proportion ofhardening agent.

3. Apparatus according to claim 2 in which the epoxy resin is adiglycidyl ether of bisphenol A and the hardening agent is a member ofthe group consisting of polyfunctional primary and secondary amines,tertiary amines, organic carboxylic acids and organic carboxylic acidanhydrides.

4. Apparatus according to claim 1 in which the die box is lined with aplastic which is of high molecular weight selected from the groupconsisting of epoxy resin, polyethylene, Micarta, polypropylene andnylon.

References Cited by the Examiner UNITED STATES PATENTS 288,240 11/1883Ittner 25-122 849,214 4/1907 Markle et al. 25-122 1,260,002 3/ 1918Lanhotfer. 2,520,570 8/1950 Short 25-7 2,836,530 5/1958 Rees 113-492,846,742 8/1958 Wagner 18-47 2,856,637 10/1958 Daniel 18-47 2,965,94612/1960 Sweet et al. 25-7 2,967,756 1/ 1961 Mazzucchelli et al. 18-472,972,785 2/1961 Touceda 18-47 3,041,989 7/1962 Tanner. 3,101,065 8/1963Kalis. 3,124,092 3/ 1964 Raynes.

FOREIGN PATENTS 789,094 1/ 1958 Great Britain.

OTHER REFERENCES The Tool Engineer, March 1959, pages and 106 reliedupon.

ROBERT F. WHITE, Primary Examiner.

MAURICE V. BRINDISI,

ALEXANDER H. BRODMERKEL, Examiners.

1. APPARATUS FOR PRESSING DETERGENT MATERIALS INTO CAKE FORM COMPRISINGA PAIR OF RELATIVELY MOVABLE COMPANION DIE MEMBERS AND A DIE BOX, SAIDMOVABLE DIE MEMBERS EACH HAVING A WORKING SURFACE OF HARD, RIGIDTHERMOSET EPOXY RESIN POLYMER AND BEING SUBSTANTIALLY COMPOSED OF SAIDPOLYMER, THE MOVABLE DIE MEMBERS BEING OF SHAPE WHICH CONFORMS WITH THEDIE BOX WALLS AND CLEARS THEM, THE CLEARANCE SPACE BEING SMALL ENOUGH TOPREVENT FLASHING OF DETERGENT PAST THE DIES DURING PRESSING, SAID EPOXYRESIN POLYMER HAVING IMPACT STRENGTH OF ABOUT 0.2 TO 1 FT. LB PER INCHOF NOTCH, ROCKWELL